Models of Cuspy Triaxial Galaxies

Abstract

We construct numerical models of mildly triaxial elliptical galaxies with central density cusps. Using a technique we call "adiabatic squeezing," we begin with a spherical gamma = 1 Hernquist model and apply a drag to the velocities of the particles along each principal axis. The final models are stable in isolation, preserving their density structure and figure shape over many dynamical timescales. The density profile and axial ratios compare well to the observed properties of elliptical galaxies. The orbital structure of these models show a mixture of tubes, boxes, and boxlets, as expected for triaxial systems, with very few chaotic orbits. These N-body realizations of cuspy triaxial galaxies provide a basis for the study of dynamical evolution of elliptical galaxies.